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Re: C11 threads ABI questions - enum values
- From: Rich Felker <dalias at libc dot org>
- To: "Joseph S. Myers" <joseph at codesourcery dot com>
- Cc: Roland McGrath <roland at hack dot frob dot com>, libc-alpha at sourceware dot org
- Date: Fri, 3 Oct 2014 11:19:17 -0400
- Subject: Re: C11 threads ABI questions - enum values
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On Fri, Oct 03, 2014 at 10:40:23AM +0000, Joseph S. Myers wrote:
> On Thu, 2 Oct 2014, Rich Felker wrote:
>
> > ways that require ABI decisions (O_SEARCH, O_EXEC, NI_NUMERICSCOPE, and
> > O_TTY_INIT are the examples that come to mind immediately) where it
> > would be really nice to have either some direction from glibc, or at
> > least a tenative assignment of values planned.
>
> O_* are shared with the Linux kernel, so values need to be agreed there to
> avoid conflict with any new features added to the kernel in future (even
> if part of the semantics is implemented in userspace). Once the values
> are defined in the kernel's uapi headers, that determines them for all C
> libraries.
The kernel position is that O_SEARCH and O_EXEC can be done by
userspace in terms of O_PATH, but I'm not sure that's correct. There's
an old thread (I think libc-alpha was CC'd on it but I'm not sure)
about that. O_TTY_INIT could probably be done in userspace too and
that might be what they expect us to do for it, too...
Rich